Hi Schemers,
I would like to branch based on unification, like Erlang, so I can get a
"case" form on steroids, which would bind free variables and match
structure and constants, ("destructuring"?). I was wondering if I should
be using match.ss to do this. If so, could someone point me to a simpler
example than an implementation of the Y-operator? (The Y-operator. Wow.
It's kind of funny.)
I want to be able to do something like the following, where
"case-on-steroids" is my desired operator:
(define (choose input)
(case-on-steroids (X Y) ; define X and Y as free variables
((X X Y) (+ X Y)) ; matches (input 1 1 2), bind X->1, Y->2
((1 X (2 Y) X) (* X Y)) ; matches (input 1 100 '(2 300) 100)
; X->100, Y->300
(_ 'whatever)))) ; matches anything no bindings
My model for this is the pattern matching way of defining procedures in
Erlang, which, in turn, is derived from Prolog.
It looks like define-syntax has pattern matching like I want, and having
fenders would be great too, but I want to use the facility as a glorified
case statement.
Any pointers would be much appreciated. If match.ss can do this, I
apologize for giving up on the documentation.
Thanks in advance,
Webb Sprague
Programmer III
Wildlife Fish Conservation Biology
University of California at Davis
One Shields Avenue
Davis, CA 95616